Measuring an irradiance of an incident beam on a target object, and reconstruction of an irradiance pattern was previously accomplished by use of a two-dimensional (2-D) detector matrix device. The 2-D detector matrix device may be placed on the target object, and receive the incident beam directly. The incident beam is measured at locations on the 2-D detector matrix device. Manufacturing complexity makes systems for directly receiving the incident beam using the 2-D detector matrix device expensive with a long lead time.
Alternatively, a reflected beam may be reflected from the target object receiving the incident beam, and received by the 2-D detector matrix device. The reflected beam is measured at locations on the 2-D detector matrix device as a representation of the incident beam. A location for the 2-D detector matrix device must be provided that is not co-planar with a sensed region of the target object, which may be difficult for an object like a missile due to aerodynamics. Furthermore, other target objects may be difficult because the 2-D detector matrix device may interfere with the reflected beam of the target object.